MONTPELIER — The debate over campaign finance in Vermont has focused squarely on elections for public office. Some lawmakers, however, are now looking to shine a brighter light on the influence of money in the legislative process.

A flurry of radio advertisements related to the soda tax in recent weeks has prompted new calls for heightened disclosure requirements. Lobbyists, or the special interests that hire them, are already required to file expense reports with the secretary of state three times per year.

But Rep. Mike Fisher, a Lincoln Democrat and chairman of the House Committee on Health Care, said the infrequency of those deadlines prevents lawmakers from getting timely information about the monied interests trying to sway their votes on controversial bills.

“I think it’s totally appropriate for anybody with an interest in legislation to spend as much money as they want to influence our decisions,” Fisher said. “I just want to know how much.”

Fisher wants to take a page from the laws that govern the 30-day run-up to elections, when anyone running an ad for or against a candidate has to file a finance report within 24 hours of it airing. Fisher’s committee drafted a memorandum this week seeking a similar standard for expenditures that try to influence lawmakers’ votes on specific bills.

Mass media expenditures include things like radio and television ads, but also ads in local newspapers and mass mailings to constituents.

In much the same way that candidates and political action committees use media to influence elections, lobbyists and special-interest groups use it to sway the outcome of votes on key bills. This year has already featured two ad-generating issues in “death with dignity” and the soda tax.

Fisher said he was moved to act after asking veteran Montpelier lobbyist Andrew MacLean how much the beverage associations he represents had paid to run the anti-soda-tax messages that have appeared recently in print and radio ads. The ads encourage voters to contact their legislators and register their opposition to the proposal.

Fisher said MacLean told him he’d get back to him with the information. Fisher said though that another member of MacLean’s firm, Heidi Tringe, later told him he’d get the answer on the next mandated disclosure deadline, which doesn’t come until April.

“Our committee is debating this issue now, so that’s not a really useful timetable,” Fisher said. “I’m of the belief that if money is being spent to influence a political process, then it needs to be part of the record.”

The American Heart Association, a proponent of the soda tax, has been running ads in favor of the penny-per-ounce surcharge. Tina Zuk, director of government affairs for the organization, voluntarily provided Fisher with information detailing her group’s $3,000 worth of mass media buys.

“We have nothing to hide and we’re doing it for a great cause,” Zuk said. “(Fisher) said he’s interested in learning sooner than later about how money spent on media might be affecting the political process, and we’re happy to provide him with the information.”

MacLean’s firm, MacLean Meehan Rice, declined comment.

Paul Burns, executive director of the Vermont Public Interest Research Group, has overseen mid-session media campaigns on everything from renewable energy subsidies to bottle-deposit bills.

“It works,” Burns said. “It’s always hard to know precisely what caused someone to make a call to their legislator, and whether it caused that person to vote a certain way. But it’s mass communication, and it helps to create a certain public sentiment around an issue.”

Burns said he’s not opposed to real-time disclosure requirements for legislative advocacy. But he said the Legislature should make sure it doesn’t expose itself to legal challenges. The restrictions on political speech during elections, Burns said, are designed to prevent the kind of quid pro quo corruption that might arise when a candidate owes the people that got him or her into office.

“That same fear of course does not apply when we are looking at issue of advancing or trying to stop specific pieces of legislation,” Burns said. “But you still have a state interest it seems to me, and a public interest, in knowing who is sponsoring those ads and how much they’re spending.”

Fisher said the memorandum will be sent to the chairwomen of the House and Senate committees on government operations, where they’ll be considered alongside a slate of other campaign-finance provisions being debated this year.